278 Chapter11·HighAvailability:ResettoGood Configuring High Availability Each virtualization vendor has its own unique details and steps in order to configure high availability, but virtually all of them have the same basic requirements and configurations to enable high availability in the environment. These include: Shared storage Network infrastructure that monitors for failure A pool or cluster of servers that participates in high availability Configuring Shared Storage A common element in most virtualization high availability configurations is the requirement for all of the virtualization hosts to use a common shared storage system that the virtual machine files reside on. The reason for this is simple: in order for a virtual machine to run on a host, the host has to be able to read the virtual machine files. If the virtual machine files are stored in local storage on HOSTA and HOSTA fails, it is not possible for HOSTB to read the virtual machine files. However, if the